Descartes' Error: Emotion, Reason, and the Human Brain is a 1994 book by neuroscientist António Damásio describing the physiology of rational thought and decision, and how the faculties could have evolved through Darwinian natural selection.

[2][3] Written for the layperson, Damásio uses the dramatic 1848 railroad accident case of Phineas Gage as a reference for incorporating data from multiple modern clinical cases, enumerating damaging cognitive effects when feelings and reasoning become anatomically decoupled.

Among his experimental evidence and testable hypotheses, Damásio presents the "somatic marker hypothesis", a proposed mechanism by which emotions guide (or bias) behavior and decision-making, and positing that rationality requires emotional input.

He argues that René Descartes' "error" was the dualist separation of mind and body, rationality and emotion.

J. Birtchnell, The Two of Me: The Rational Outer Me and The Emotional Inner Me (London 2003) J. Panksepp, Affective Neuroscience (OUP 1998)